Asphalt pavement



UNITED STATES PATENT OFFICE.

GEORGE E. SIMPSON AND JAMES SIMPSON, OF NEWTON, MASSACHUSETTS.

'ASPHALT PAVEMENT.

SPECIFICATION forming part of Letters Patent No. 242,162, dated May 31, 1881,

Application filed April 13, 1881. (No specimens.) 4

To all whom it may concern:

Be it known that we, GEORGE F. SIMPsoN and JAMES SlMrsoN, both of the city of Newton, in the county of Middlesex and State of Massachusetts, have invented an Asphalt Pavement, of which the following is a specification.

Asphalt paving compositions are usually made from either natural asphalt or the pitch residuum 0t coal-tar, and they have heretofore contained gravel and other ingredients which have a tendency to harden the pitch y portions.

In this composition we use for the body of the composition gravel with a certain proportion of fine loam to thicken and harden and absorb the pitchy cement. The mixture forming. the body of the concrete is composed of nine parts of clean gravel and one part of fine loam. The gravel should be passed through a half-inch screen, and the partwhich passes through the screen is used. Nine parts of this screened gravel and one part of fine loam are heated and intimately mixed with a composition composed of about fifty-seven gallons of thepavin g-cement made from coal-tar or prepared from natural asphaltum, which is about as thick as the ordinary black pitch of commerce, such as will stand alone when the barrel is broken 011' from it, and to this fifty-seven gallons of paving-cement heated five gallons of crude coal-tar are added, The crude coaltar is such as would be liquid at ordinary atmospheric temperatures. This composition of sixty-two gallons of pitchy or asphaltic material is mixed with thirty-six cubic feet of the gravel and loam mixture described, and the ingredients are thoroughly incorporated together hot, and are applied to the prepared surfaces, either of rolled gravel or macadam,or the common worn stone or wood pavement, and thoroughly rolled or rammed or compressed upon this prepared surface of gravel, macadam, or old pavement. When cool this concrete is quite hard and somewhat deficient in elasticity. In order to correct this defect an application of hot paving-cement is made to the surface with a mop or broom. This paving-cement is not as hard as that previously described, but is about as thick as the old-fashioned su gar-house molasses at ordinary temperatures, but when heated is almost as fluid as water. This application softens the surface of the pavemen t, fills porous places, and renders the concrete tougher than it would otherwise be, and when applied it isimmediately covered with the fine gravel before mentioned, or with crushed quartz, or with coarse sand, and when it is covered is rolled in the usual way.

This pavement is quite elastic and not liable to become sticky. The top surface of sand and coal-tar is very similar to a tar and graveled roof when the gravel used is fine, and the loam employed absorbs the asphalt, and thus allows the use of a larger portion of bituminous material.

It will be observed that this pavement is practically of one continuous body from bottom to top, and is a very simple pavement to prepare and lay. It can be patched, when worn, very readily, and may be resurfaced at very slight cost and trouble.

We claim as our invention and desire to secure by Letters Patent- A pavement composed of the following materials, in substantially the following proportions: thirty-six (36) cubic feet of a mixture of nine parts of gravel and one part fine loam with fifty-seven gallons of pitchy paving-cement and five gallons of crude coal-tar, prepared, laid, and surfaced substantially as hereinbefore described.

ciao. I SIMPSON. JAMES SIMPSON. Witnesses:

F. F. RAYMOND, 2d, W. O. Foes. 

